Beneficial effects of normovolemic hemodilution on coronary collateral flow and myocardial injury in the early phase of myocardial ischemia / 中国病理生理杂志

ABSTRACT

The effects of decreasing .blood viscosity through hemodilution on coronary collateral flow and myocardial injury in the.early phase of myocardial ischomia were studied in 21 open-chest anaesthetized dogs. It was shown that after 30 rain of coromary occlusion the low-shear viscosity of the whole blood (?bl) began to increase gradually, while the collateral flow (CF) decreased concomitantly. At the 75-min postocclusion, ?bl increased by 18.1?3.9%, CF decreased by 24.1 ?4.6%, ST-segment of epicardial electrogram elevated significantly and the ultrastructural changes were characterized by severe mitochondrial damage, autolysis of myofilaments and blood cell obstruction in the micro vessel etc. In the hemodilution group, the chamges i1~ ~qbl and CF of the first 30-min postocclusion were quite the same as that of the control group. Following mild isovolemic hemodilution performed at the 30-min postocclusion, all of the ischemic changes improved significantly. At the 75-min postocclusion, contrary to the control group, ?bl decreased by 25.5?3.9% and CF increased by 54,7?10.8% as compared to the control value, the previously elevated ST segment decreased markedly and the ultrastructural injury alleviated to a great degree as well. The experimental results suggest that the deleterious hemorheologic changes in the early phase of myocardial ischemia is a major factor of aggravating ischemic myocardial injury and the decrese in blood viscosity through hemodilution may have protective effect on ischemic myocardium by increasing the collateral flow.